Electric lamp base construction



Dec. 22, 1964 L. H. VERBEEK 3,152,502

ELECTRIC LAMP BASE CONSTRUCTION Filed April 26, 1961 2 Sheets-Sheet 1 INVENTOR LEO H. VERBEEK.

BY a

AGENT Dec. 22, 1964 L. H. VERBEEK ELECTRIC LAMP BASE CONSTRUCTION Filed April 26, 1961 2 Sheets-Sheet 2 INVENTOR LEO H. VERBEEK.

BY ,8 W AGEN$ United States Patent Ofifice 3,l2,5d2 Patented Dec. 22, 1964 3,162,502 ELECTRIC LAMP BASE CONSTRUCTION Leo Henricus Verheek, Emmasingei, Eindhoven, Netherlands, assignor to North American Philips Company,

Inc, New York, N.Y., a corporation of Delaware Filed Apr. 26, 1961, Ser. No. 126,732 Claims priority, application Netherlands May 2, 1%0 4 Claims. (Cl. 339-144) The invention relates to an electric lamp, which is provided with a central contact and a side contact which is structurally separated from said center contact, which contacts are each connected to one of the current supply wires extending towards the pinch, and in which the neck of the lamp is provided with a pressed-in, possibly interrupted, helical profile. In this lamp, the central contact and the side contact constitute structurally separated members in contrast with what is usual in the normal commercial incandescent lamps. The advantage is that, when designing the construction of each of these contacts, the construction or design of the other of these contacts need not be taken into account. As a result of this, it is not only possible to come to a decrease of the cost price of the finished lamp in certain cases, but also to a simpler mounting of these contacts, so that mechanization in the manufacture of the lamps may be carried through, if desired, even further than was usual so far.

The present invention relates to an improvement of the side contact of an electric lamp. Such a lamp may be an electric incandescent lamp but also a lamp in which a discharge tube is the light-emitting member. The lamp in question is provided with a lamp cap which is con structed so that such a lamp may be screw-connected to a lampholder.

According to the present invention, the lamp of the above type is characterized in that around the profiled part of the neck of the lamp a thin material foil pressed in this profile and having at least one electrically conduc tive surface is provided, one of the current supply Wires, extending towards the pinch, being connected in an electrically conductive manner to this foil.

It is surprising that the possibility exists to obtain in this manner a simple solid side contact for such an electric lamp. It has appeared that, starting from a Hat metal foil, the deformability of this foil is suflicient to deform it, by means of a simple compression apparatus, such as a punch or a pair of tongs manufactured for the purpose, to a material layer situated in the profile. The foil preferably consists of metal, for example aluminum, and has a thickness of at most 100 microns, preferably at most 50 microns.

According to a further embodiment of the invention, the neck of the envelope is provided with a groove extending substantially parallel to the axis of the lamp, in which groove one of the current supply wires is situated. In this manner, there is no danger that the wire is not damaged when engaging and disengaging respectively the lamp manufactured in this manner into and out of the associated lampholder.

It is of advantage to provide this wire in the ends of the foil folded together for this purpose. In this case, the part of the current supply wire extending along the neck of the lamp and surrounded by the ends of the foil may be situated in the groove in the neck of the lamp.

In order that the invention may be readily carried into eliect, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which 7 FIG. 1 is a longitudinal sectional view of the upper part of an electric lamp according to the invention,

FIGS. 2, 3 and 4 show three stages of the manufacture of the side contact in the lamp according to the invention. I

In the lamp shown, the neck 2 of the envelope and the edge 3 of the stem 4 projecting outwards are fused together at the end face 1 of the envelope. After fusing, a helical profile 5 is compressed into the glass neck 2 of the envelope. The current supply wires are provided in the pinch 6 of the lamp. The current supply wire 7 leads to the central contact 8. The current supply wire 9 is connected to the side contact of the lamp. The exhaust tube 10 is provided inside the stem 4.

External lamp contacts which are structurally separated from each other are used in the lamp according to the invention. The central contact 8 which comprises a metal bushing 9a, containing the end of the current supply wire '7 which is attached to said bushing by means of a drop of solder, is supported by a cap 11 of insulating material provided with a bore. This cap is attached to the end face 1 of the envelope by means of cement or an adhesive 12.

The side contact separated structurally from this central contact comprises a strip of aluminum foil 14 having a thickness of approximately 50 microns. As appears from the diagrammatic FIGS. 2, 3 and 4, this strip 14 in this embodiment is provided around the neck of the lamp 2., which, for clearness sake, is shown circular, in a manner such that the ends 15 and 16 of this strip approximately coincide. The end 17 of the current supply wire 9 is now made to engage the end 16 of the strip (or is provided between the two strips). Then the ends 16 and 17 of the foil 14 are provided around the wire 17, the resulting assembly is rolled, stretched tightly around the neck of the lamp and the resultingroll is provided in a groove 18 which is compressed in the neck of the lamp 2 and which extends in that neck in the longitudinal direction of the lamp. Once this stage is reached, in which consequently the metal foil 14 still has a flat surface, this foil is deformed, by means of a tool not shown, for example a pair of tongs or a punch, so that it locally engages the screw thread on the neck of the lamp, in which manipulation the foil i permanently deformed. As a result of this, the foil firmly engages the surface of the neck of the lamp. It has appeared that by this manipulation the end 17 of the wire is so firmly held by the foil that neither for the electric contact, nor for its mechanical attachment is it strictly necessary to use a soldering or welding connection between the end of this wire and the foil.

What is claimed is:

1. An electric lamp base construction provided with a pair of current supply wires'comprising a lamp base having a central contact and a peripheral groove therein, a lamp cap shell portion being structural separate from said lamp base and constituting a thin foil pressed into engagement with the periphery of said lamp base and having at least one conductive surface, one of said current supply members being'connected to said central contact, and a side conductor connected to the other of said current supply wires and electrically connected to the end parts of said foil, said side conductorrand end parts of said foil, being located in said peripheral groove of said lamp base.

2. An electriclamp as claimed in claim 1 whereinsaid foil is constituted of metal.

3. An electric lamp as claimed in claim 1 wherein said foil has a maximum thickness of microns.

4. An electric lamp base construction provided with a pairof current supply wires comprising a lamp base having a central contact and a peripheral groove therein, A

r t v. "31 r 4 a lamp cap shell, portion being structural. separatefrom- V saidconductor andvsaidw end parts beinglocated in said said lamp base and constituting a thin foil pressed into peripheral groove of said lampbase.

- engagement with the periphery of said lamp base and having 'a t. legs; ue rmdpctiv esurface egg of cm- References Cited in the file Of this patent refltrsqpply m b e i .w nefl rla q saict en ra r 5 UNITED STATES-PATENTS tact, and a side'conductorconnected to the other of said 1 437,723 l I current supply, wires and electrically and; mechgnically oug 13 1922 connected t9 the end pgrts of sa id fpil, said;end parts of; I 13650289 I Mc-Ginley- N 225 1927 he il be n app o d a d ev c nd t an H943 Wanamake? 1931 

1. AN ELECTRIC LAMP BASE CONSTRUCTION PROVIDED WITH A PAIR OF CURRENT SUPPLY WIRES COMPRISING A LAMP BASE HAVING A CENTRAL CONTACT AND A PERIPHERAL GROOVE THEREIN, A LAMP CAP SHELL PORTION BEING STRUCTURAL SEPARATE FROM SAID LAMP BASE AND CONSTITUTING A THIN FOIL PRESSED INTO ENGAGEMENT WITH THE PERIPHERY OF SAID LAMP BASE AND HAVING AT LEAST ONE CONDUCTIVE SURFACE, ONE OF SAID CURRENT SUPPLY MEMBERS BEING CONNECTED TO SAID CENTRAL CONTACT, AND A SIDE CONDUCTOR CONNECTED TO THE OTHER OF SAID CURRENT SUPPLY WIRES AND ELECTRICALLY CONNECTED TO THE END PARTS OF SAID FOIL, SAID SIDE CONDUCTOR AND END PARTS OF SAID FOIL, BEING LOCATED IN SAID PERIPHERAL GROOVE OF SAID LAMP BASE. 